A balloon-borne apparatus consisting of an emulsion target, spark chambers, and an ionization spectrometer has been used to study properties of nuclear interactions of cosmic rays in the energy range 10-300 GeV. The ionization spectrometer, used to measure the energies $E_{\mathrm{sp}}$ of the primaries passing through the apparatus, was calibrated at accelerator energies. This calibration was extrapolated to higher energies using Monte Carlo calculations. A comparison of energy estimates obtained using emulsion methods with $E_{\mathrm{sp}}$ indicates that for proton interactions the method based on constancy of transverse momentum and inelasticity gives an energy $1.5E_{\mathrm{ch}}$ that is too large by a factor of only 1.1 ± 0.2, whereas the method of Castagnoli gives an energy $E_{\mathrm{Cast}}$ that is too large by a factor of 5 ± 2. For interactions of $Z>\mathrm{}1\mathrm{}$ primaries, estimates ($E_p$ and $E_{\alpha }$) based on the opening angle of fragments and the $1.5E_{\mathrm{ch}}$ estimates are in good agreement with $E_{\mathrm{sp}}$. It is found that if the depth of the first interaction of each primary is known to within ±1/4 interaction length, the spectrometer estimate is not sensitive to some other characteristics of the first interaction, such as number and angular distribution of charged secondary particles. For proton interactions with fewer than six black and gray tracks, $E^{\frac{1}{4}}$ and $\ln E$ functions give better fits to the data on the mean number of minimum-ionizing secondaries vs $〈E_{\mathrm{sp}}〉$ than the $E^{\frac{1}{2}}$ function does.

Close

PrevNext

View figure in article